--- Wnn/jutil/dtoa.c.orig
+++ Wnn/jutil/dtoa.c
@@ -53,6 +53,9 @@ static char *rcs_id = "$Id: dtoa.c,v 1.9 1994/06/28 02
   */
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 #include "commonhd.h"
 #include "config.h"
 #include "jslib.h"
@@ -89,7 +92,7 @@ struct wnn_file_head file_head;
 
 char *hinsi_file_name = NULL;
 
-void
+int
 main(argc, argv)
 int argc;
 char **argv;
